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HFCutilized
R410A
NOTE: RoHS compliant products have <G> mark on the spec name plate.
PARTS CATALOG (OBB739)
Models
MXZ-2DM40VA - E1 , ET1 , ER1
MXZ-3DM50VA - E1 , ET1 , ER1
CONTENTS
1. TECHNICAL CHANGES ··································· 22. PART NAMES AND FUNCTIONS ····················· 33. SPECIFICATION ················································ 44. NOISE CRITERIA CURVES ······························ 65. OUTLINES AND DIMENSIONS ························ 76. WIRING DIAGRAM ············································ 97. REFRIGERANT SYSTEM DIAGRAM ············· 108. PERFORMANCE CURVES ····························· 139. ACTUATOR CONTROL ··································· 19
10. SERVICE FUNCTIONS ···································· 2011. TROUBLESHOOTING ····································· 2412. DISASSEMBLY INSTRUCTIONS ···················· 50
INDOOR UNITS COMBINATION SHEETS
Indoor unit service manualMSZ-DM•VA Series (OBH750)MSZ-HJ•VA Series (OBH647)
MXZ-2DM40VA
SERVICE MANUALNo. OBH739
REVISED EDITION-A
OUTDOOR UNIT
Revision A:• MXZ-2DM40VA - ER1 and MXZ-
3DM50VA - ER1 have been added.
Please void OBH739.
2
<Preparation before the repair service> Prepare the proper tools. Prepare the proper protectors. Provide adequate ventilation. After stopping the operation of the air conditioner, turn off the power-supply breaker and remove the power plug. Discharge the capacitor before the work involving the electric parts.
<Precautions during the repair service> Do not perform the work involving the electric parts with wet hands. Do not pour water into the electric parts. Do not touch the refrigerant. Do not touch the hot or cold areas in the refrigeration cycle. When the repair or the inspection of the circuit needs to be done without turning off the power, exercise great caution not to
touch the live parts.
Use the specifi ed refrigerant onlyNever use any refrigerant other than that specified.Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.Correct refrigerant is specified in the manuals and on the spec labels provided with our products.We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by failure to follow the instructions.
TECHNICAL CHANGES1
MXZ-2DM40VA - E1 , ET1 , ER1
MXZ-3DM50VA - E1 , ET1 , ER1
1. New model
Revision A:• MXZ-2DM40VA - ER1 and MXZ-3DM50VA - ER1 have been added.
OBH739A
3
PART NAMES AND FUNCTIONS2
ACCESSORIES
MXZ-2DM40VAAir inlet
Air outlet
Drain outlet
Piping
Drain hose
(Back and side)
Model MXZ-2DM40VA MXZ-3DM50VADrain socket 1 1Drain cap 2
Air outlet
Drain outlet
Air inlet(Back and side)
MXZ-3DM50VA
OBH739A
4
SPECIFICATION3
Outdoor model MXZ-2DM40VA
Outdoor unit power supply Single phase230 V, 50 Hz
Sys
tem
Indoor units number 2Piping total length m Max. 30Connecting pipe length m Max. 20Height difference (Indoor ~ Outdoor) m Refer to 7 REFRIGERANT SYSTEM DIAGRAM.Height difference (Indoor ~ Indoor) m Refer to 7 REFRIGERANT SYSTEM DIAGRAM.Function Cooling HeatingCapacity Rated frequency (Min.-Max.) 2 kW 4.0 (1.1 - 4.3) 4.3 (1.0 - 4.7)Breaker capacity A 15
Ele
ctric
al d
ata
Power input (Total) 1, 2 W 1,050 1,160Running current (Total) 1, 2 A 5.1 5.6Power factor (Total) 1, 2 % 90Starting current (Total) 1, 2 A 5.6
Coeffi cient of performance (C.O.P) (Total) 1, 2 3.81 3.71
Com
pres
sor Model KNB092FFDHC
Output W 1,100Current 1, 2 A 4.7 5.2Refrigeration oil (Model) L 0.32 (NEO22)
Fan
mot
or Model RC0J50-FACurrent 1, 2 A 0.19 0.23Dimensions W x H x D mm 800 x 550 x 285Weight kg 32
Spe
cial
rem
arks
Air fl ow (Rated) m3 /h 1,752 1,914Sound level (Rated) dB(A) 48 52Fan speed (Rated) rpm 840 910Refrigerant fi lling capacity (R410A) kg 0.95
1 Measured under rated operating frequency.2 When connected with below indoor units.
MSZ-DM25VA + MSZ-DM25VANOTE: Test conditions are based on ISO 5151. (Refrigerant piping length (one way): 5 m)COOLING INDOOR Dry-bulb temperature 27.0 °C Wet-bulb temperature 19.0 °C OUTDOOR Dry-bulb temperature 35.0 °C Wet-bulb temperature 24.0 °CHEATING INDOOR Dry-bulb temperature 20.0 °C OUTDOOR Dry-bulb temperature 7.0 °C Wet-bulb temperature 6.0 °C
OBH739A
5
Outdoor model MXZ-3DM50VA
Outdoor unit power supply Single phase230 V, 50 Hz
Sys
tem
Indoor units number 2 to 3Piping total length m Max. 50Connecting pipe length m Max. 25Height difference (Indoor ~ Outdoor) m Refer to 7 REFRIGERANT SYSTEM DIAGRAM.Height difference (Indoor ~ Indoor) m Refer to 7 REFRIGERANT SYSTEM DIAGRAM.Function Cooling HeatingCapacity Rated frequency (Min.-Max.) 2 kW 5.0 (2.7 - 6.5) 6.0 (2.4 - 7.5)Breaker capacity A 25
Ele
ctric
al d
ata
Power input (Total) 1, 2 W 1,130 1,310Running current (Total) 1, 2 A 5.0 5.8Power factor (Total) 1, 2 % 99Starting current (Total) 1, 2 A 5.8
Coeffi cient of performance (C.O.P) (Total) 1, 2 4.42 4.58
Com
pres
sor Model SNB130FGBH1T
Output W 1,300Current 1, 2 A 4.5 5.3Refrigeration oil (Model) L 0.7 (NEO22)
Fan
mot
or Model SIC-71FW-F764-1Current 1, 2 A 0.20 0.23Dimensions W x H x D mm 840 x 710 x 330Weight kg 57
Spe
cial
rem
arks
Air fl ow (Rated) m3 /h 2,252 2,379Sound level (Rated) dB(A) 50 53Fan speed (Rated) rpm 630 660Refrigerant fi lling capacity (R410A) kg 2.7
1 Measured under rated operating frequency.2 When connected with below indoor units.
MSZ-DM25VA + MSZ-DM25VA + MSZ-DM25VANOTE: Test conditions are based on ISO 5151. (Refrigerant piping length (one way): 5 m)COOLING INDOOR Dry-bulb temperature 27.0 °C Wet-bulb temperature 19.0 °C OUTDOOR Dry-bulb temperature 35.0 °C Wet-bulb temperature 24.0 °CHEATING INDOOR Dry-bulb temperature 20.0 °C OUTDOOR Dry-bulb temperature 7.0 °C Wet-bulb temperature 6.0 °C
OBH739A
6
90
80
70
60
50
40
30
20
1063 125 250 500 1000 2000 4000 8000
APPROXIMATETHRESHOLD OFHEARING FORCONTINUOUSNOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCT
AVE
BAND
SO
UND
PRES
SURE
LEV
EL, d
B re
0.0
002
MIC
RO B
AR
BAND CENTER FREQUENCIES, Hz
CoolingHigh
FUNCTIONFAN SPEED
HeatingHigh
48
SPL(dB(A))
52
LINE
NOISE CRITERIA CURVES4
MXZ-2DM40VA
90
80
70
60
50
40
30
20
1063 125 250 500 1000 2000 4000 8000
APPROXIMATETHRESHOLD OFHEARING FORCONTINUOUSNOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCT
AVE
BAND
SO
UND
PRES
SURE
LEV
EL, d
B re
0.0
002
MIC
RO B
AR
BAND CENTER FREQUENCIES, Hz
CoolingHigh
FUNCTIONFAN SPEED
HeatingHigh
50
SPL(dB(A))
53
LINEMXZ-3DM50VA
OUTDOOR UNIT
MICROPHONE1m Test conditions
Cooling :Dry-bulb temperature 35°C Wet-bulb temperature 24°C Heating :Dry-bulb temperature 7°C Wet-bulb temperature 6°C
OBH739A
7
OUTLINES AND DIMENSIONS5
MXZ-2DM40VAUnit: mm
OBH739A
8
1.Installation space
Note : Leave front and both sides free of obstruction.
Note : Leave rear, overhead and both sides free of obstruction.
500
or m
ore
100 or more
Note : Leave front and overhead free of obstruction.
100 or more 350 or more
200
or m
ore
500
or m
ore
2.Service space
100
or m
ore
500
or m
ore
350 or more350 or more
100 or moreService space
Liquid pipe : Ø6.35(flared)1/4 C unit connection
B unit connection
A unit connection
Gas pipe : Ø9.52(flared)3/8Liquid pipe : Ø6.35(flared)1/4Gas pipe : Ø9.52(flared)3/8Liquid pipe : Ø6.35(flared)1/4Gas pipe : Ø9.52(flared)3/8
MXZ-3DM50VAUnit: mm
OBH739A
9
WIRING DIAGRAM6
MXZ-2DM40VA - E1 , ET1 , ER1
21S4
NAME
4
t°t°
S3
N
L
12-24V
~ 230V
S3
L
N 12-24V
~ 230V
N
L
ACL, ACL2C61~63DB61
F701, 801, 901 F1
IC700, 820, 932IC802
LED1, 2
SYMBOL
/
NOTES:
RT68
TB1~3T801
X63, 64, 6621S4
SYMBOLNAMELEV A, B
MCMF
PTC64, 65RT61RT62RT64RT65
SYMBOLNAME
:Terminal block
1. About the indoor side electric wiring refer to the indoor unit electric wiring diagram for servicing.2. Use copper conductors only. (For field wiring).3. Symbols below indicate.
:Connector
t°t°
MF
-~
+
~
MC
LEV A
X64
PTC64
1
31CN644
4CN641
RT68RT62t°
RT61
CN9357
CN7251
5
M
LEV B
F701
LD61
6 1CN724
6
5
M
PTC65
X63
CN72121
X66
1 3CN722
TO INDOORUNIT No. B
TO INDOORUNIT No. A
POWER SUPPLY~/N230V 50Hz
BLK
BLU
BLK
BLU
RED
ORN
ACL2
TB3
TB2
BLK
BLU
BREAKERCIRCUIT
GRN/YLWTB1
F1
3
LD66B
LD62
CN602
5
CN601
1
LD-E1
LD-E2
1
BLK
BLU
BLK
BRNBLK
BLU
RED
ORN
LED1 LED2
CN936 OUTDOORDISPLAYP.C. BOARD
71
7
3 1
3 1
MS3~
W VU
RED WHT
F901
T801F801
IC802+
C62
+
C61C63
+
ACL
1 2CN642
BRNORN
35
1CN931
MS3~
5 121CN643
RT65RT64
INVERTER P.C. BOARD
IC700
CNMC
P
UVW
NIC932
N
PU
W
V
DB61
IC820
CN9321
3
LD66ALD70
LDW
LDV
LDU
RED
BLK
WHT
RED
BLK WHTBLK
REACTORSMOOTHING CAPACITORDIODE MODULEFUSE (T3.15AL250V)FUSE (T3.15AL250V)POWER MODULEPOWER DEVICELED
EXPANSION VALVE COILCOMPRESSORFAN MOTORCIRCUIT PROTECTORDEFROST THERMISTORDISCHARGE TEMP. THERMISTORFIN TEMP. THERMISTORAMBIENT TEMP. THERMISTOR
OUTDOOR HEAT EXCHANGERTEMP. THERMISTORTERMINAL BLOCKSWITCHING TRANSRELAYREVERSING VALVE COIL
MXZ-3DM50VA - E1 , ET1 , ER1
X712 X714
OUTDOORPOWER P.C.BOARD
+
CB1
+
CB2
+
CB3
BLK
CN661
1 8
CN665
21
RT65t°
RT62t°
RT68RT61t°t°
(WHT) (WHT)(RED)CN791CN793
(BLU)CN792
LEV C
M
LEV B
M
LEV A
M
5
1 6
5
1 6
5
1 6
CN621
1
CN611
3
CN601
1
3
5
1
YLW
ORN
BLK
BLU
RED
TO INDOORUNIT No.C S3
LN
YLW
BLU
BLK
TO INDOORUNIT No.B S3
LN
BLU
ORN
BLK
S3TO INDOORUNIT No.A
LN
BLK
RED
BLU
BLK
BLU
TB2
TB3
TB4
BLKBLK
F66
5
CN3
51
F930
MF
5 MS3~
CN7
211
CN904
2
F711
CN7121 2
CN7141 2
CN6231
CN71131
12-24V
12-24V
12-24V
LED1
IC801
1 6
5
4
~ 230V
~ 230V
~ 230V
HPS
CN681
21
CN5
2
CN931
CN702
CN795
1
CN2
S
CN701 1
1
2
7
1
R
1
2
CN801
U
CN9
LD9
3
7
F801
V
1
CN4
4
IPM
LED2
1
T801
PFC
W
21
LED3
1
LD2
t°
2
3
7 LD1LDE1
CN9031
TAB4
2
3
1
X64
5
CN61
CN901
F64
3
1
POWER SUPPLY~/N 230V 50Hz
BLK
WHT
RED
YLW
BLKBLK
BLK
BLKBLKBLK
BLK
L
BLK
BLK
RE
D
WH
T
21S4
BLK
RT64
M
LEV E
MC
MS3~V
BLK
WHT
RED
U
W
BLK
BLUNL
CIRCUITBREAKER
TB1
TAB2
TAB1
F65
GRN/YLW
NOISE FILTER P.C.BOARD
OUTDOOR CONTROL P.C.BOARD
PTC65
PTC64
RELAYREVERSING VALVE SOLENOID COIL
X712,71421S4
SYMBOL SYMBOL SYMBOL SYMBOL SYMBOL NAMENAMENAMENAMENAMECB1~3
F64F65, 66
F711, 801, 930HPS
SMOOTHING CAPACITORFUSE (T2AL250V)FUSE (T6.3AL250V)
FUSE (T3.15AL250V)
HIGH PRESSURE SWITCH
RT64RT65RT68T801
TB1~4X64
FIN TEMP. THERMISTORAMBIENT TEMP. THERMISTOROUTDOOR HEAT EXCHANGER TEMP. THERMISTORTRANSFORMERTERMINAL BLOCKRELAY
MCMF
PFCPTC64, 65
RT61RT62
COMPRESSORFAN MOTORPOWER FACTOR CONTROLLERCIRCUIT PROTECTIONDEFROST THERMISTORDISCHARGE TEMP. THERMISTOR
IC801IPM
LLED1, 2, 3LEV A~C
LEV E
POWER DEVICEPOWER MODULEREACTORLEDEXPANSION VALVE COILEXPANSION VALVE COIL
NOTES: 1. About the indoor side electric wiring refer to the indoor unit electric wiring diagram for servicing. 2. Use copper conductors only (For field wiring). 3. Symbols below indicate. :Terminal block :Connector
OBH739A
10
UNIT: mm (inch)
MXZ-2DM40VA
a
b
Outdoorunit
Indoorunits
15 m
10 m
15 m
Max.Height difference
Outdoor unit union diameterFor
Indoor unit A Liquid 6.35(1/4)Gas 9.52(3/8)
Indoor unit B Liquid 6.35(1/4)Gas 9.52(3/8)
Stop valve(with strainer #100)
LEV A
LEV B
Compressor
Muffler
4-way valveIndoor unit
B
Indoor unitA
Indoor unitA
Indoor unitB
Capillary tube
Capillary tube
Stop valve(with strainer #100)
Refrigerant flow in coolingRefrigerant flow in heating
Dischargetemperaturethermistor RT62
Stop valve(with service port)
Stop valve(with service port)
Strainer#100
Sub muffler
Defrost thermistorRT61
Ambienttemperature thermistor RT65
Outdoor heatexchangertemperaturethermistorRT68
FAN-OUT
HE
X-O
UT
UNIT: mm
REFRIGERANT SYSTEM DIAGRAM7
MAX REFRIGERANT PIPING LENGTHPiping length each indoor unit (a, b) 20 mTotal piping length (a+b) 30 mBending point for each unit 20Total bending point 30It is irrelevant which unit is higher.
ADDITIONAL REFRIGERANT CHARGEOutdoor unit precharged
(g)
Refrigerant piping length (one way, 2 unit total)
20 m 30 m
950 0 200
Calculation: Xg = 20 g/m x (Refrigerant piping length (m) - 20)
Refrigerant pipe diameter is different according to indoor unit to be connected. When using extension pipes, refer to the right table.
When diameter of refrigerant pipe is different from that of outdoor unit union, use optional Different-diameter pipe.
For further information on Different-diameter pipe, refer to "PARTS CATALOG".
OBH739A
11
Strainer#100
Powerreceiver
LEV A
LEV B
LEV C
Oil separator
Compressor
Defrost thermistorRT61
Distributor
Muffler
4-way valve
LEV E
Indoor unitC
Indoor unitB
Indoor unitA
Indoor unitA
Indoor unitB
Indoor unitC
Capillary tube
Capillary tube
Capillary tube
Capillary tube
Capillary tube
Dischargetemperaturethermistor RT62
Strainer#100
Strainer#100
Strainer#100
R.V. coil OFF ON
Refrigerant flow in coolingRefrigerant flow in heating
Ambienttemperature thermistor RT65
Outdoor heatexchangertemperaturethermistorRT68
FAN-OUT
HE
X-O
UT
Strainer#100
Stop valve withservice port
Stop valve
High-pressure switch
UNIT: mm (inch)
UNIT: mmMXZ-3DM50VA
MAX REFRIGERANT PIPING LENGTH
Outdoor unit union diameterFor
Indoor unit A Liquid 6.35(1/4)Gas 9.52(3/8)
Indoor unit B Liquid 6.35(1/4)Gas 9.52(3/8)
Indoor unit C Liquid 6.35(1/4)Gas 9.52(3/8)
a
b
c
Outdoorunit
Indoorunits
15 m
10 m
15 m
Max.Heightdifference
Piping length each indoor unit (a, b, c) 25 mTotal piping length (a+b+c) 50 mBending point for each unit 25Total bending point 50It is irrelevant which unit is higher.
Refrigerant pipe diameter is different according to indoor unit to be connected. When using extension pipes, refer to the right table.
When diameter of refrigerant pipe is different from that of outdoor unit union, use optional Different-diameter pipe.
For further information on Different-diameter pipe, refer to "PARTS CATALOG".
ADDITIONAL REFRIGERANT CHARGEOutdoor unit precharged
(g)
Refrigerant piping length (one way, 3 unit total)
40 m 50 m
2,700 0 200
Calculation: Xg = 20 g/m x (Refrigerant piping length (m) - 40)
OBH739A
12
When relocating or disposing of the air conditioner, pump down the system following the procedure below so that no refrigerant is released into the atmosphere.1) Turn off the breaker.2) Connect the gauge manifold valve to the service port of the stop valve on the gas pipe side of the outdoor unit.3) Fully close the stop valve on the liquid pipe side of the outdoor unit.4) Turn on the breaker.5) Start the emergency COOL operation on all the indoor units.6) When the pressure gauge shows 0.05 to 0 MPa [Gauge] (approximately 0.5 to 0 kgf/cm²), fully close the stop valve on the gas
pipe side of the outdoor unit and stop the operation. (Refer to the indoor unit installation manual about the method for stopping the operation.) * If too much refrigerant has been added to the air conditioner system, the pressure may not drop to 0.05 MPa [Gauge] (approxi-mately 0.5 kgf/cm²), or the protection function may operate due to the pressure increase in the high-pressure refrigerant circuit. If this occurs, use a refrigerant collecting device to collect all of the refrigerant in the system, and then recharge the system with the correct amount of refrigerant after the indoor and outdoor units have been relocated.
7) Turn off the breaker. Remove the pressure gauge and the refrigerant piping.
When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes. The compressor may burst and cause injury if any foreign substance, such as air, enters the pipes.
WARNING
PUMPING DOWN
OBH739A
13
PERFORMANCE CURVES8
The standard specifications apply only to the operation of the air conditioner under normal conditions.Since operating conditions vary according to the areas where these units are installed, the following information has been pro-vided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.(1) GUARANTEED VOLTAGE 198 - 264 V 50 Hz(2) AIR FLOW Air flow should be set at MAX.(3) MAIN READINGS (1) Indoor intake air wet-bulb temperature : °CWB (2) Indoor outlet air wet-bulb temperature : °CWB (3) Outdoor intake air dry-bulb temperature : °CDB (4) Total input: W (5) Indoor intake air dry-bulb temperature : °CDB (6) Outdoor intake air wet-bulb temperature : °CWB (7) Total input : W
Indoor air wet and dry bulb temperature difference on the left side of the following chart shows the difference between the indoor intake air wet and dry bulb temperature and the indoor outlet air wet and dry bulb temperature for your reference at service.
How to measure the indoor air wet and dry bulb temperature difference1. Attach at least 2 sets of wet and dry bulb thermometers to the indoor air intake as shown in the figure, and at least 2 sets
of wet and dry bulb thermometers to the indoor air outlet. The thermometers must be attached to the position where air speed is high.
2. Attach at least 2 sets of wet and dry bulb thermometers to the outdoor air intake. Cover the thermometers to prevent direct rays of the sun.3. Check that the air filter is cleaned.4. Open windows and doors of room.5. Press the EMERGENCY OPERATION switch once (twice) to start the EMERGENCY COOL (HEAT) MODE.6. When system stabilizes after more than 15 minutes, measure temperature and take an average temperature.7. 10 minutes later, measure temperature again and check that the temperature does not change.
INDOOR UNIT OUTDOOR UNIT
}}
Cooling
Heating
Wet and dry bulbthermometersBACK VIEW
Wet and dry bulbthermometersFRONT VIEW
MXZ-2DM40VA MXZ-3DM50VA
OBH739A
14
8-1. CAPACITY AND THE INPUT CURVES MXZ-2DM40VA
Outdoor intake air Dry-bulb temperature (°C)46454645
Outdoor intake air Dry-bulb temperature (°C)
Indoor intake air Wet-bulb temperature (°C) Indoor intake air Wet-bulb temperature (°C)
6.7
6.1
5.6
5.1
4.6
4.1
25 c
lass
7.4
6.8
6.2
5.6
5.1
4.5
35 c
lass
Indo
or a
ir W
et-b
ulb
tem
pera
ture
diffe
renc
e (°C
)
Outdoor intake air Wet-bulb temperature (°C) Outdoor intake air Wet-bulb temperature (°C)
Indoor intake air Dry-bulb temperature (°C)
Indoor intake air Dry-bulb temperature (°C)
20.6
19.0
17.4
15.8
14.3
12.7
11.1
9.5
25 c
lass
22.9
21.1
19.3
17.6
15.8
14.1
12.3
10.5
35 c
lass
Indo
or a
ir Dr
y-bu
lb te
mpe
ratu
redi
ffere
nce
(°C)
Indo
or a
ir W
et-b
ulb
tem
pera
ture
diffe
renc
e (°
C)
Outdoor intake air Dry-bulb temperature (°C)46454645
Outdoor intake air Dry-bulb temperature (°C)
Indoor intake air Wet-bulb temperature (°C) Indoor intake air Wet-bulb temperature (°C)
50 c
lass
7.4
6.8
6.2
5.6
5.1
4.5
6.7
6.1
5.6
5.1
4.6
4.1
10.5
9.6
8.7
7.9
7.1
6.3
35 c
lass
25 c
lass
MXZ-3DM50VA
50 c
lass
24.722.820.919.017.115.213.311.4
35 c
lass
20.619.017.415.814.312.711.19.5
25 c
lass
22.921.119.317.615.814.112.310.5In
door
air
Dry-
bulb
tem
pera
ture
diffe
renc
e (°C
)
Outdoor intake air Wet-bulb temperature (°C) Outdoor intake air Wet-bulb temperature (°C)
Indoor intake air Dry-bulb temperature (°C)
Indoor intake air Dry-bulb temperature (°C)
OBH739A
15
<COOL>Capacity
FrequencyHz
<COOL>Total input
0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
<COOL>Capacity
FrequencyHz
<COOL>Total input
0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
<HEAT>Capacity <HEAT>Total input
FrequencyHz0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
2.0
<HEAT>Capacity <HEAT>Total input
FrequencyHz0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
25-class unitMXZ-2DM40VA
35-class unit
8-2. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY (single operation)
OBH739A
16
25-class unit<COOL>Capacity
FrequencyHz
<COOL>Total input
0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
<COOL>Capacity
FrequencyHz
<COOL>Total input
0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
<COOL>Capacity
FrequencyHz
<COOL>Total input
0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
<HEAT>Capacity <HEAT>Total input
FrequencyHz0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
<HEAT>Capacity <HEAT>Total input
FrequencyHz0 50 100 150
0.5
1.0
1.5
FrequencyHz0 50 100 150
0.5
1.0
1.5
<HEAT>Capacity <HEAT>Total input
FrequencyHz0 50 100 150
0.5
1.0
1.5
2.0
FrequencyHz0 50 100 150
0.5
1.0
1.5
2.0
MXZ-3DM50VA
35-class unit
50-class unit
OBH739A
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1. Press EMERGENCY OPERATION switch to start COOL or HEAT mode (COOL: Press once, HEAT: Press twice).2. Test run operation starts and continues to operate for 30 minutes.3. Compressor operates at rated frequency.4. Indoor fan operates at High speed.5. After 30 minutes, test run operation finishes and EMERGENCY OPERATION starts (Operation frequency of compressor varies).6. To cancel test run operation or EMERGENCY OPERATION, press EMERGENCY OPERATION switch or any button on remote controller.
8-3. HOW TO OPERATE FIXED-FREQUENCY OPERATION <Test run operation>
Both indoor and outdoor units are under the same temperature/humidity condition.
Operation: TEST RUN OPERATION (Refer to 8-3.)
Dry-bulb temperature ( ) Relative humidity (%)
20 50
25 60
30 70
8-4. OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT CURVE (single operation)NOTE: The unit of pressure has been changed to MPa on the international system of units (SI unit system). The conversion factor is: 1 (MPa [Gauge]) = 10.2 (kgf/cm2 [Gauge])(1) COOL operation
MXZ-2DM40VA 25-class unit
Out
door
low
pre
ssur
e
(MPa[Gauge])
Out
door
uni
t cur
rent
(A)
Ambient temperature ( )Ambient humidity (%)
Ambient temperature ( )Ambient humidity (%)
50 60 70 (%) (%)50 60 70
42Hz
42Hz
1514
13
12
11
10
9
87
15 20 25 30 350.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
15 20 25 30 350
1
2
3
4
5
Out
door
low
pre
ssur
e
(MPa[Gauge])
Out
door
uni
t cur
rent
(A)
Ambient temperature ( )Ambient humidity (%)
Ambient temperature ( )Ambient humidity (%)
50 60 70 (%) (%)50 60 70
42Hz
42Hz
1514
13
12
11
10
9
87
15 20 25 30 350.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
15 20 25 30 350
1
2
3
4
5
35-class unit
MXZ-3DM50VA 25-class unit
Out
door
low
pre
ssur
e
(MPa[Gauge])
Out
door
uni
t cur
rent
(A)
Ambient temperature ( )Ambient humidity (%)
Ambient temperature ( )Ambient humidity (%)
50 60 70 (%) (%)50 60 70
40Hz
40Hz
1514
13
12
11
10
9
87
15 20 25 30 350.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
15 20 25 30 350
1
2
3
4
5
35-class unit
Out
door
low
pre
ssur
e
(MPa[Gauge])
Out
door
uni
t cur
rent
(A)
Ambient temperature ( )Ambient humidity (%)
Ambient temperature ( )Ambient humidity (%)
50 60 70 (%) (%)50 60 70
40Hz
40Hz
1514
13
12
11
10
9
87
15 20 25 30 350.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
15 20 25 30 350
1
2
3
4
5
50-class unit
Out
door
low
pre
ssur
e
(MPa[Gauge])
Out
door
uni
t cur
rent
(A)
Ambient temperature ( )Ambient humidity (%)
Ambient temperature ( )Ambient humidity (%)
50 60 70 (%) 50 60 70
40Hz40Hz
1514
13
12
11
10
9
87
(%)15 20 25 30 350.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
15 20 25 30 350
1
2
3
4
5
OBH739A
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Condition:
Operation: TEST RUN OPERATION (Refer to 8-3.)
(2) HEAT operation
Dry bulb temperature (°C)Indoor20.014.5
21
Outdoor76
1512
20.014.5Wet bulb temperature (°C)
MXZ-2DM40VA 25-class unit
0 5 10 15 20 250
1
2
3
4
5
Ambient temperature ( )
48Hz
Out
door
uni
t cur
rent
(A)
0 5 10 15 20 250
1
2
3
4
5
Ambient temperature ( )
48Hz
Out
door
uni
t cur
rent
(A)
35-class unit
25-class unit 35-class unitMXZ-3DM50VA
50-class unit
0 5 10 15 20 253
4
5
6
7
8
Ambient temperature ( )
47Hz
Out
door
uni
t cur
rent
(A)
0 5 10 15 20 253
4
5
6
7
8
Ambient temperature ( )
47Hz
Out
door
uni
t cur
rent
(A)
0 5 10 15 20 253
4
5
6
7
8
Ambient temperature ( )
47Hz
Out
door
uni
t cur
rent
(A)
OBH739A
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ACTUATOR CONTROL9
Relation between main sensor and actuator
Sensor PurposeActuator
Compressor LEV Outdoor fan motor R.V. coil
Discharge temperature thermistor Protection
Indoor coil temperature thermistorCooling: Coil frost preventionHeating: High pressure protection
Defrost thermistor Heating: DefrostingFin temperature thermistor ProtectionAmbient temperature thermistor Control/Protection
Outdoor heat exchanger temperature thermistor Cooling: Control/Protection
Capacity code Control
MXZ-2DM40VA MXZ-3DM50VA
OBH739A
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Outdoor display P.C. board
SW1 SW2ON
1 2 3 4 5 6
ON
SERVICE FUNCTIONS10
10-1. THE POSITION OF SWITCHMXZ-2DM40VA MXZ-3DM50VA
MXZ-2DM40VA
ONSW1
ONSW1
Cool/Dry Heat
With this function, you can lock the operation mode of the outdoor unit. Once the operation mode is locked to either COOL/DRY mode or HEAT mode, the air conditioner operates in that mode only.Default setting is required to activate this function. Please explain this function to your customers and ask them whether they want to use it.
[How to lock the operation mode](1) Turn OFF the breaker and make sure that the LED goes off. (2) Set SW1 or SW2 as shown in the figure below. (3) Turn ON the breaker.
10-2. LOCKING THE OPERATION MODE OF THE AIR CONDITIONER (COOL, DRY, HEAT)
MXZ-2DM40VASW1 on the outdoor display P.C. board
ON
5 6
SW2ON
5 6
SW2Cool/Dry Heat
MXZ-3DM50VASW2 on the outdoor control P.C. board
MXZ-3DM50VA
Oudoor control P.C. board
ONSW2
SW871
1 2 3 4 5 6
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10-3. LOWERING THE OPERATING NOISE OF THE OUTDOOR UNITWith this function, you can lower the operating noise of the outdoor unit when the operation load is small, for example, during night time in COOL mode. However, note that the cooling and heating capacity can also be lowered if this function is activated.Default setting is required to activate this function. Please explain this function to your customers and ask them whether they want to use it.
[How to lower the operating noise](1) Turn OFF the breaker and make sure that the LED goes off. (2) Set the "3" Switch of SW1 to ON to enable this function. (MXZ-2DM40VA) Set the "3" Switch of SW2 to ON to enable this function. (MXZ-3DM50VA)(3) Turn ON the breaker.
ONSW1
MXZ-2DM40VASW1 on the outdoor display P.C. board
ON
5 6
SW2
MXZ-3DM50VASW2 on the outdoor control P.C. board
10-4. AUTOMATIC LINE CORRECTING This outdoor unit has an automatic line correcting function which automatically detects and corrects improper wiring or piping.<MXZ-2DM40VA>Improper wiring or piping can be automatically detected when one indoor unit is operated in COOL mode for 30 minutes.When improper wiring or piping is detected, wiring lines are corrected (A to B/ B to A) with the software.
NOTE: This function may not work due to the condition or environment of the unit, such as the following: - gas leak, closed stop valve - unit failure such as defective LEV - indoor/outdoor temperature
NOTE: This function does not work when the "2" of SW2 on the outdoor display P.C. board is turned OFF.
SW2
<Correct>
Indoor/outdoorconnecting wire
Terminalblock
Refrigerant pipe
Indoor unit B
Liquid/Gas pipe
Indoor unit AOutdoor unit
<Incorrect wiring>
Terminalblock
Indoor unit B
Liquid/Gas pipe
Indoor unit AOutdoor unit
<Incorrect piping>
Terminalblock
Indoor unit B
Liquid/Gas pipe
Indoor unit AOutdoor unit
BA
BA
BA
BA
BA
BA
MXZ-2DM40VASW2 on the outdoor display P.C. board
OBH739A
22
The record of automatic line correcting can be checked in the following way:(1) Turn OFF the breaker and make sure that the LED goes off. (2) Turn ON the "3" of SW2 on the outdoor display P.C. board. (3) Turn ON the breaker. (4) Check the correction state with the LED lamps on the outdoor display P.C. board. (5) Turn OFF the breaker and make sure that the LED goes off. (6) Turn OFF the "3" of SW2 on the outdoor display P.C. board.(7) Turn ON the breaker.
Number of blinksWiring line
LED1 (Red) LED2 (Yellow)Once Once Not corrected
3 times 3 times Corrected SW2
<MXZ-3DM50VA>Improper wiring or piping can be automatically detected by pressing the piping/wiring correction switch (SW871) on the outdoor control P.C. board.When improper wiring or piping is detected, wiring lines are corrected.This will be completed in about 10 to 20 minutes.
[How to activate this function]
1. Check that outside temperature is above 0ºC. (This function does not work when outside temperature is not above 0ºC. )2. Check that the stop valves of the liquid pipe and gas pipe are open.3. Check that the wiring between indoor and outdoor unit is correct. (If the wiring is not correct, this function does not work.)4. Turn ON the breaker and wait at least 1 minute.5. Press the piping/wiring correction switch (SW871) on the outdoor P.C. board. Do not touch energized parts.
LED indication during detection:LED1 (Red) LED2 (Yellow) LED3 (Green)
Lighted Lighted Once
LED indication after detection:LED1 (Red) LED2 (Yellow) LED3 (Green) Indication
Lighted Not lighted Lighted Completed (Problem corrected/Normal)Once Once Once Not completed (Detection failed)
Other indications Refer to "SAFETY PRECAUTIONS WHEN LED FLASHES" located behind the service panel.
Make sure that the valves are open and the pipes are not collapsed or clogged.
6. Press the switch to cancel. LED indication after cancel:
LED1 (Red) LED2 (Yellow) LED3 (Green)Lighted Lighted Not lighted
NOTE: Indoor unit cannot be operated while this function is activated. When this function is activated while indoor unit is operating, the operation will be stopped. Operate indoor unit after the automatic line correcting is finished. Pressing the switch during detection cancels this function.
The record of automatic line correcting can be checked in the following way:Press the switch for more than 5 secondsLED will show the record of automatic correcting for about 30 seconds as shown in the table below:
Number of blinksWiring line
LED1 (Red) LED2 (Yellow) LED3 (Green)Once Once Lighted Not corrected
3 times 3 times Lighted Corrected
NOTE: Activate this function to check the correct wiring after replacing the outdoor P.C. board. (Previous records are deleted when the outdoor control P.C. board is replaced.) The record cannot be shown if automatic line correcting is not cancelled (Refer to "How to activate this function").
MXZ-2DM40VASW2 on the outdoor display P.C. board
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10-5. PRE-HEAT CONTROL If moisture gets into the refrigerant cycle, or when refrigerant is liquefied and collected in the compressor, it may interfere the start-up of the compressor. To improve start-up condition, the compressor is energized even while it is not operating to generate heat at the winding.The compressor uses about 50 W when pre-heat control is turned ON. Pre-heat control is OFF(MXZ-2DM40VA) / ON (MXZ-3DM50VA) at the default setting.
MXZ-3DM50VA[How to activate pre-heat control](1) Turn OFF the breaker and make sure that the LED goes off. (2) Set the “4” of SW2 as shown figure below to OFF to activate pre-heat control function.(3) Turn ON the breaker.
MXZ-2DM40VA[How to activate pre-heat control](1) Turn OFF the breaker and make sure that the LED goes off. (2) Set the “4” of SW2 as shown figure below to ON to activate pre-heat control function.(3) Turn ON the breaker.
NOTE: Pre-heat control will be turned OFF when the breaker is turned OFF.
SW2 on the outdoor display P.C. boardSwitch Pre-heat control
SW2
Deactivated(Factory setting) Activated
SW2 on the outdoor control P.C. boardSwitch Pre-heat control
SW2
Activated(Factory setting) Deactivated
OBH739A
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11 TROUBLESHOOTING
3. Troubleshooting procedure1) Check if the OPERATION INDICATOR lamp on the indoor unit is fl ashing on and off to indicate an abnormality. To
make sure, check how many times the OPERATION INDICATOR lamp is fl ashing on and off before starting service work.
2) Before servicing, check that the connector and terminal are connected properly.3) When the P.C. board seems to be defective, check the copper foil pattern for disconnection and the components for
bursting and discoloration.4) Refer to 11-2, 11-3 and 11-4.
11-1. CAUTIONS ON TROUBLESHOOTING1. Before troubleshooting, check the following:
1) Check the power supply voltage.2) Check the indoor/outdoor connecting wire for miswiring.
2. Take care of the following during servicing1) Before servicing the air conditioner, be sure to turn OFF the unit fi rst with the remote controller, and after confi rming
the horizontal vane is closed, turn OFF the breaker and/or disconnect the power plug.2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the P.C. board.3) When removing the electrical parts, be careful of the residual voltage of smoothing capacitor.4) When removing the P.C. board, hold the edge of the board with care NOT to apply stress on the components.5) When connecting or disconnecting the connectors, hold the connector housing. DO NOT pull the lead wires.
11-2. FAILURE MODE RECALL FUNCTIONThis air conditioner can memorize the abnormal condition which has occurred once.Even though LED indication listed on the troubleshooting check table (11-4.) disappears, the memorized failure details can be recalled.
1. Flow chart of failure mode recall function for the indoor/outdoor unit Refer to the service manual of indoor unit.
MXZ-2DM40VA MXZ-3DM50VA
Lead wiring Connector housing
<Incorrect> <Correct>
OBH739A
25
2. Flow chart of the detailed outdoor unit failure mode recall function
2.Blinking pattern when outdoor unit is abnormal:
ONOFF
No beep BeepsRepeated cycle
2.5-second OFF 3-second ONBlinking at 0.5-second interval
No beep BeepsRepeated cycle
2.5-second OFF 3-second ONBlinking at 0.5-second interval
Repeated cycle
Does the OPERATION INDICATOR lamp on the indoor unit blink at the interval of 0.5 seconds?Blinks: The outdoor unit is abnormal. Beep is emit-
ted at the same timing as the blinking of the OPERATION INDICATOR lamp. 2
Yes (Blinks)
No (OFF)
The outdoor unit might be abnormal.Check if outdoor unit is abnormal according to the following procedures.
Operational procedure
With the remote controller headed towards the indoor unit, press the TEMPERATURE buttons to adjust the set temperature to 25 °C. 1
1 Regardless of normal or abnormal condition, 2 short beeps are emitted as the signal is received.
The outdoor unit is abnormal.Check the blinking pattern, and make sure that the abnormal point with the outdoor unit failure mode table (11-2.3.).Make sure to check at least 2 consecutive blinking cycles. 2
Repair the failure parts.
The outdoor unit is normal.
Release the failure mode recall function. 3
NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly. 2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
Delete the memorized abnormal condition. 3
Release the failure mode recall function. 3
3 Refer to the service manual of indoor unit.
Release the failure mode recall function. 3
Make sure that the remote controller is set to the failure mode recall function.3
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3. Outdoor unit failure mode tableMXZ-2DMUpper lamp of OPERATION INDICATOR lamp (Indoor
unit)
Abnormal point(Failure mode/protection)
LED indication(Outdoor P.C. board)
Condition Remedy
Indoor/outdoor
unit failure mode recall
function
LED 1 LED 2
OFF None (Normal) Not lighted Not lighted — — —2-time fl ash Outdoor power system Lighted Lighted Overcurrent protection cut-out operates
3 consecutive times within 1 minute after the compressor gets started.Compressor protection cut-out operates 24 consecutive times within 10 seconds after the compressor gets started.
• Check the compressor con-necting wire.
• Refer to 11-6. "Check of inverter/compressor".
• Check the stop valve.○
3-time fl ash Discharge temperature thermistor
Lighted Once Thermistor shorts or opens during compressor running.
• Refer to 11-6. "Check of outdoor thermistors". ○
Defrost thermistor Lighted Once ○Ambient temperature thermistor
Lighted Twice ○Fin temperature thermistor Lighted 3 times ○P.C. board temperature thermistor
Lighted 4 times • Replace the inverter P.C. board. ○
Outdoor heat exchanger temperature thermistor
Lighted 9 times • Refer to 11-6. "Check of outdoor thermistors". ○
4-time fl ash Overcurrent Once Not lighted
The overcurrent fl ows into intelligentpower module.
• Check the compressor con-necting wire.
• Refer to 11-6. "Check of inverter/compressor".
• Check the stop valve.
—
Compressor Twice Not lighted
The overcurrent fl ows into intelligent power module within 10 seconds after the compressor gets started.( The compressor gets restarted in 15 seconds.)
• Check the compressor con-necting wire.
• Refer to 11-6. "Check of inverter/compressor".
—
9 times Not lighted
Waveform of compressor current is dis-torted. —
5-time fl ash Discharge temperature Lighted Lighted Discharge temperature exceeds 116ºCduring operation.
• Check the refrigerant circuit and the refrigerant amount.
• Refer to 11-6. "Check of LEV".
—
6-time fl ash High pressure Lighted Lighted The outdoor heat exchanger temperature exceeds 70ºC during cooling or the in-door gas pipe temperature exceeds 70ºC during heating.
• Check the refrigerant circuit and the refrigerant amount.
• Check the stop valve. —
7-time fl ash Fin temperature 3 times Not lighted
The fi n temperature exceeds 90ºCduring operation.
• Check the around outdoor unit.
• Check the outdoor unit air passage.
—
P.C. board temperature 4 times Not lighted
The P.C. board temperature exceeds80ºC during operation.
• Refer to 11-6. "Check of outdoor fan motor". —
8-time fl ash Outdoor fan motor Lighted Lighted Failure occurs 3 consecutive times within 30 seconds after the fan gets started.
• Refer to 11-6. "Check of outdoor fan motor". —
9-time fl ash Nonvolatile memory data Lighted 5 times Nonvolatile memory data cannot be read properly.
• Replace the inverter P.C. board. ○
Power module 7 times Not lighted
The output of the power module that drove the compressor was shorted or the winding of the compressor wasshorted.
• Refer to 11-6. "Check of inverter/compressor". ○
10-time fl ash Discharge temperature Lighted Lighted The discharge temperature is kept under 50ºC (COOL mode)/40ºC (HEAT mode) for more than 40 minutes.
• Check the refrigerant circuit and the refrigerant amount.
• Refer to 11-6. "Check of LEV".
—
11-time fl ash Current sensor 8 times Not lighted
The sensor circuit of current of compressor shorts or opens duringcompressor operate.
• Replace the inverter P.C. board. ○
Bus-bar voltage 6 times Not lighted
The bus-bar voltage exceeds 430 V orfalls to 50 V or below during compressor operating.
• Check the power supply.• Replace the inverter P.C.
board. ○14-time fl ash Stop valve Lighted 12 times The current of compressor is power
module is out of order.• Check the stop valve.• Check the refrigerant circuit
and the refrigerant amount.○
17 time fl ash Outdoor refrigerant systemabnormality
Lighted 17 times A closed valve and air trapped in the refrigerant circuit are detected based on the temperature sensed by the indoor and outdoor thermistors and the current of the compressor.
• Check for a gas leak in a con-necting piping etc.
• Check the stop valve.• Refer to 11-6. "Check of
outdoor refrigerant circuit".
○
NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (11-4).
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The frequency of the compressor is kept 80Hz or more and the discharge temperature is kept under 50°C (cooling)/40°C (heating)for more than 40 minutes.
Abnormal point(Failure mode/protection)
Condition RemedyIndoor/outdoor
unit failure moderecall function
LED indication(Outdoor P.C. board)LED 1 LED 2
OFF2-time flash
3-time flash
4-time flash
5-time flash
6-time flash
7-time flash
8-time flash
Lighted LightedLighted Lighted
Lighted Once
Lighted OnceLighted TwiceLighted 3 timesLighted 4 times
Lighted 9 times
Once Not lighted
Lighted Lighted
Lighted Lighted
3 times Not lighted
4 times Not lighted
Lighted Lighted
Lighted Lighted
Lighted 5 times9-time flash
10-time flash
Replace the outdoor control P.C. board.
Replace the outdoor control P.C. board.
circuit and the refrigerant amount.
Refer to 11-6. "Check of LEV".
Reconnect compressor connector.
Refer to 11-6. "How to check inverter/ compressor".
Check the stop valve.
circuit and the refrigerant amount.
Check the stop valve.
Refer to 11-6. "Check of outdoor fan motor".
circuit and the refrigerant amount.
Refer to 11-6. "Check of LEV".
door unit.
air passage. "Check
of outdoor fan motor".
of the compressor connecting wire.
"How to check inverter/compressor".
Refer to 11-6. "Check of outdoor thermistors".
Refer to 11-6. "Check of outdoor thermistors".
Overcurrent protection cut-out operates 3 consecutive times within 1 minute after the compressor gets started, or converter protection or bus-bar voltage protection cut-out operates 3 consecutive times within 3 minutes after start-up.
Thermistor shorts or opens during compressor running.
28 A current flows into intelligent power module.
Discharge temperature exceeds 116°Cduring operation. Compressor can restart if dischargetemperature thermistor reads 100°C or less 3 minutes later.High-pressure is detected with the high-pressure switch (HPS) during operation.
The outdoor heat exchangertemperature exceeds 70°C during cooling or the indoor gas pipe temperature exceeds 70°C during heating. The fin temperature exceeds 89°Cduring operation.
The P.C. board temperature exceeds 73°C during operation.
Failure occurs 3 consecutivetimes within 30 seconds after the fan gets started.
Nonvolatile memory data cannot be read properly.
Outdoor power system
Discharge temperaturethermistor
Defrost thermistorAmbient temperature thermistorFin temperature thermistorP.C. board temperaturethermistor
Overcurrent
Discharge temperature
High pressure
Fin temperature
P.C. board temperature
Outdoor fan motor
Nonvolatile memory data
Discharge temperature
None (Normal)
Upper lamp of OPERATION INDICATORlamp (Indoor unit)
Outdoor heat exchangertemperature thermistor
NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (11-4).
MXZ-3DM
OBH739A
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11-time flash
15-time flash
Check the connecting wire between the outdoor control P.C. board and the power P.C. board.
Replace the power P.C. board.
Check the connecting wire between the control P.C. board, the noise filter P.C. board and the power P.C. board.
Check the voltage of the power supply.
power P.C. board.
Check the voltage of the power supply.
control P.C. board.
Refer to 11-6. "Check of LEV".
Check the drain pump of the indoor unit.
The communication between boards protection cut-out operates 2 consecutive times.
Communication error occursbetween the electronic control P.C.board and power board for morethan 10 seconds.
Current sensor protection cut-out operates 2 consecutive times.
A short or open circuit is detected in the current sensor during compressor operating.
The protection cut-out of the zero cross detecting circuit operates 10 consecutive times.
Zero cross signal cannot be detected while the compressor is operating.
A failure is detected in the operation of the converter during operation.
The bus-bar voltage exceeds 400 V or falls to 200 V or below during compressor operating.The bus-bar voltage exceeds 400 V or falls to 50V or below during compressor operating.
Communication errorbetween P.C. boards
Current sensor
Zero cross detecting circuit
Converter
Bus-bar voltage(1)
Bus-bar voltage(2) Even if this protection stop isperformed continuously threetimes, it does not mean theabnormality in outdoor powersystem.
LEV and drain pump
Lighted 6 times
Lighted 7 times
5 times Notlighted
5 times Notlighted
5 times
6 times
Notlighted
Notlighted
The indoor unit detects an abnormality in the LEV and drain pump.
Lighted Lighted
Abnormal point(Failure mode/protection)
Condition RemedyIndoor/outdoor
unit failure moderecall function
LED indication(Outdoor P.C. board)LED 1 LED 2
Upper lamp of OPERATION INDICATOR
lamp (Indoor unit)
NOTE: Blinking patterns of this mode differ from the ones of "Troubleshooting check table" (11-4).
Operation start
Check the outdoor unitLED indicator.
Refer to 11-6. "Check of power supply".
• Indoor unit serial signal error Refer to 11-6. "How to check miswiring and serial signal error".
• COOL or HEAT operation only Refer to 11-6. "Check of R.V. coil"
• When heating, room does not get warm.• When cooling, room does not cool. Refer to 11-6. "How to check of inverter/compressor". Check mispiping, shortage of capacity
• When cooling, heat exchanger of non- operating indoor unit frosts.• When heating, non operating indoor unit gets warm. Refer to 11-6. "Check of LEV".
• When cooling, dew drops in the non- operating indoor unit. Check of mispiping
Refer to 11-4. "Troubleshooting check table".
Both LED 1 and LED 2 are lighting.
LED 1 or LED 2has blinked.
Both LED 1 and LED 2 are OFF.
11-3. INSTRUCTION OF TROUBLESHOOTING• Check the indoor unit by referring to the indoor unit service manual, and confirm whether there is any problem in the indoor
unit.Then, check the outdoor unit by referring to this page.
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11-4. TROUBLESHOOTING CHECK TABLE MXZ-2DM
No.
1
2
3
4
5
6
9
10
11
12
13
14
15
16
Symptom
'Outdoor unit stops and restarts 3 minutes later' is repeated.
Primary current protection
Secondary current protection
High-pressure protection
Defrosting in cooling
3 times Lighted Discharge temperatureprotection
4 times LightedLow dischargetemperature protection
Check the refrigerant circuit and the refrigerant amount.Refer to 11-6. "Check of LEV".Refer to 11-6. "Check of outdoor thermistors".
Refer to 11-6. "Check of LEV".Check the refrigerant circuit and the refrigerant amount.
These symptoms do not mean any abnormality of theproduct, but check the following points.
Check if indoor filters are clogged.Check if refrigerant is short.Check if indoor/outdoor unit air circulation is short cycled.Twice Lighted
Once Lighted
The discharge temperature exceeds 100°C during operation.
The frequency of the compressor is kept 80 Hz or more and the discharge temperature is kept under 50°C (COOL mode)/40°C (HEAT mode) for more than 40 minutes.
The input current exceeds 10 A.
The current of the compressor exceeds 17 A.
The indoor gas pipe temperature exceeds 45°C during heating.
The indoor gas pipe temperature falls 3°C or below during cooling.
Outdoor unit operates.17
18
19
20
7
8
LED1(Red) LED2(Yellow)
Lighted Twice Outdoor power system
Lighted 3 times Discharge temperaturethermistor
Outdoor heat exchangertemperature thermistor
Defrost thermistor
Lighted 7 times Nonvolatile memory data Replace the inverter P.C. board.
Abnormal point / Condition Remedy
A short circuit is detected in the thermistor during operation, or when an open circuit is detected in the thermistor after 5 minutes (in cooling) and 10 minutes (in heating) of compressor start-up.
A short circuit is detected in the thermistor during operation, or when an open circuit is detected in the thermistor after 5 minutes of compressor start-up.
A closed valve and air trapped in the refrigerant circuit are detected based on the temperature sensed by the indoor and outdoor thermistors and the current of the compressor.
Replace the inverter P.C. board.
Indication
Overcurrent protection cut-out operates 3 consecutive timeswithin 1 minute after the compressor gets started.
A short circuit is detected in the thermistor during operation, or when an open circuit is detected in the thermistor after 10 minutes of compressor start-up.
Condition
The nonvolatile memory data cannot be read properly.
Fin temperaturethermistorP.C board temperaturethermistor
Lighted 4 times
Ambient temperaturethermistor
A short or open circuit is detected in the thermistor during operation.
A short or open circuit is detected in the thermistor during operation.
5 timesLighted
Overcurrent
3 times Not lighted Discharge temperatureprotection
Fin temperatureprotection P.C. board temperatureprotection
High-pressureprotection
Replace the inverter P.C. board.Bus-bar voltageprotection
Not lighted Outdoor fan motor
8 times Not lightedCurrent sensorprotection Replace the inverter P.C. board.
Not lighted Compressor
Refer to 11-6. "Check of outdoor fan motor".
Reconnect compressor connector.Refer to 11-6. "How to check inverter/compressor". Check the stop valve.
Check the amount of gas and the refrigerant circuit.Check the stop valve.
Check the amount of gas and the refrigerant circuit.Refer to 11-6. "Check of LEV".
"Check of outdoor fan motor".
Reconnect compressor connector.Refer to 11-6. "How to check inverter/compressor". Check the stop valve.
"Check of outdoor refrigerant circuit".
Twice Not lighted
4 times Not lighted
5 times Not lighted
9 times Not lighted
18 A current flows into intelligent power module.
The bus-bar voltage exceeds 430 V or falls to 50 V or below during compressor operating.
Discharge temperature exceeds 116°C during operation. Compressor can restart if discharge temperature thermistor reads 100°C or less 3 minutes later.
The fin temperature exceeds 90°C during operation.
The P.C. board temperature exceeds 78°C during operation.
Failure occurs 3 consecutive times within 30 seconds after the fan gets started.A short or open circuit is detected in the current sensor duringcompressor operating.
The compressor does not synchronize with the operating power.
The outdoor heat exchanger temperature exceeds 70°C during cooling or indoor gas pipe temperature exceeds 70°C during heating.
Outdoor unit does not operate.
Lighted Once LEV and drain pump
Check the connection of the compressor connecting wire. Refer to 11-6. "How to check inverter/compressor". Check the stop valve.
Refer to 11-6. "Check of outdoor thermistors".
Refer to 11-6. "Check of outdoor thermistors".
Refer to 11-6. "Check of outdoor thermistors".
Refer to 11-6. "Check of LEV". Check the drain pump of the indoor unit.The indoor unit detects an abnormality in the LEV and drain pump.
Lighted 11 times
Lighted 17 times
Stop valveClosed valve
Outdoor refrigerantsystem abnormality
Closed valve is detected by compressor current. Check the stop valve.
13 times
10 times
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-
-
9 times Lighted Inverter check mode
Lighted Lighted Normal
The connector of compressor is disconnected. Inverter check mode starts.
-
5 times LightedCooling high-pressureprotection
This symptom does not mean any abnormality of theproduct, but check the following points.
Check if indoor filters are clogged. Check if refrigerant is short.Check if indoor/outdoor unit air circulation is short cycled.
The outdoor heat exchanger temperature exceeds 58°C during operation.21
LED1(Red) LED2(Yellow)Abnormal point / Condition RemedyIndication ConditionNo. Symptom
Outdoor unitoperatesnormally.
23
24
Outdoor unit operates.
Outdoor display P.C. board (Parts side)
Lighted
8 times Lighted Converter protection A failure is detected in the operation of the converter during operation.22 Check the voltage of power supply. Replace the inverter P.C. board.
LED1 LED2
ON
OFF2.5-second OFF 2.5-second OFF
0.5-second ON 0.5-second ON
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 11-7.4. 2. LED is lighted during normal operation. The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF. (Example) The flashing frequency is “2”.
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MXZ-3DM
LED1(Red) LED2(Yellow)
Lighted Twice Outdoor power system
Lighted 3 times Discharge temperaturethermistor
Outdoor heat exchangertemperature thermistor
Lighted 7 times Nonvolatile memory data
Lighted 8 times
Lighted 11 times
Lighted 12 times Zero cross detectingcircuit
Remedy
circuit is detected in the thermistor 5 minutes (in cooling) and 10
Indication
Fin temperaturethermistor
thermistor
Lighted 4 times
thermistor
5 timesLighted
3 times Not lightedDischarge temperatureprotection
Fin temperatureprotection
protection
protection
8 times Not lighted
protection (1)
protection (2)
13 times Not lighted
Lighted 8 times protection
Lighted 11 times
Lighted 12 times Zero cross detecting circuitprotection
Twice Not lighted
4 times Not lighted
5 times Not lighted
Not lighted
9 times Not lighted
or less 3 minutes
A short or open circuit is detected in the current sensor while the
Outdoor unit does not Lighted Once
1
2
3
4
5
7
9
8
10
11
12
13
14
15
17
18
19
'Outdoor unit stops and restarts 3 minutes later' is
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Primary current protection
Secondary current protection
High-pressure protection
Defrosting in cooling
3 times Lighted Discharge temperatureprotection
4 times LightedLow dischargetemperature protection
Check the refrigerant circuit and the refrigerant amount.Refer to 11-6. "Check of LEV".Refer to 11-6. "Check of outdoor thermistors".
Refer to 11-6. "Check of LEV".Check the refrigerant circuit and the refrigerant amount.
5 times LightedCooling high-pressureprotection
This symptom does not mean any abnormality of theproduct, but check the following points.
Check the indoor filters are not clogged.Check there is sufficient refrigerant.Check the indoor/outdoor unit air circulation is not short
cycling.
-
-
These symptoms do not mean any abnormality of theproduct, but check the following points.
Check the indoor filters are not clogged.Check there is sufficient refrigerant.Check the indoor/outdoor unit air circulation is not short
cycling.Twice Lighted
Once Lighted
The outdoor heat exchanger temperature exceeds 58°C during operation.
9 times Lighted Inverter check mode
Lighted Lighted Normal
The unit is operated with emergency operation switch.
-
The primary current exceeds 15 A.
The current of the compressor exceeds 12 A.
The indoor gas pipe temperature exceeds 45°C during heating.
The indoor gas pipe temperature falls 3°C or below during cooling.
The discharge temperature exceeds 100°C during operation.
The frequency of the compressor is kept 80 Hz or more and the discharge temperature is kept under 50°C (cooling) /40°C (heating) for more than 40 minutes.
LED1(Red) LED2(Yellow)Abnormal point / Condition RemedyIndication ConditionNo.
20
21
22
23
24
25
26
Outdoor unit operates normally.
Outdoor unit operates.
Symptom
Outdoor control P.C. board(Parts side)LED2 LED1
Lighted
ON
OFF2.5-second OFF 2.5-second OFF
0.5-second ON 0.5-second ON
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 11-7.2. 2. LED is lighted during normal operation. The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF. (Example) The flashing frequency is “2”.
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Part name Check method and criterionDefrost thermistor (RT61)
Fin temperature thermistor (RT64)
Ambient temperature thermistor (RT65)
Outdoor heat exchanger temperaturethermistor (RT68)
Measure the resistance with a tester.
Refer to 11-7. "TEST POINT DIAGRAM AND VOLTAGE" 1. "Inverter P.C. board", 2. "Outdoor control P.C. board " or 3. "Outdoor power P.C. board" for the chart of thermis-tor.
Discharge temperature thermistor (RT62)
Measure the resistance with a tester.Before measurement, hold the thermistor with your hands to warm it up.
Refer to 11-7. "TEST POINT DIAGRAM AND VOLTAGE" 1. "Inverter P.C. board", 2. "Outdoor control P.C. board ", for the chart of thermistor.
Compressor Measure the resistance between terminals with a tester.(Winding temperature: -10 °C - 40 °C)
Normal (Each phase)MXZ-2DM40VA MXZ-3DM50VA1.49 - 1.84 0.86 - 1.06
Outdoor fan motor
MXZ-2DM40VA
Measure the resistance between lead wires with a tester.(Part temperature: -10 °C - 40 °C)
Normal (Each phase)MXZ-2DM40VA
12 - 16
Outdoor fan motorMXZ-3DM50VA
MXZ-3DM50VARefer to 11-6. .
R.V. coil Measure the resistance with a tester. (Part temperature: -10 °C - 40 °C)Normal
MXZ-2DM40VA MXZ-3DM50VA1.2 k - 1.56 k 1.26 k - 1.62 k
Linear expansion valve Measure the resistance with a tester. (Part temperature: -10 °C - 40 °C)Color of lead wire Normal
WHT - RED
37.4 - 53.9 RED - ORNYLW - REDRED - BLU
High pressure switch (HPS)MXZ-3DM50VA MXZ-3DM50VA
Pressure Normal
HPS 3.43 0.15 MPa Close4.41 0.10 MPa Open
W
UVWHT
RED
BLK
LEV
WHT
RED
YLW
ORN
BLU
11-5. TROUBLE CRITERION OF MAIN PARTS MXZ-2DM40VA MXZ-3DM50VA
2 3W
UV
1
WHT RED BLK
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Check of power supply
• When outdoor unit does not operate, LED on outdoor P.C. board is not lighting.11-6. TROUBLESHOOTING FLOW
Turn ON the breaker.
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
+ -
Check the main power supply circuit for proper connections.
Is there voltage of 230 VAC in the power supply terminal block?
Is there voltage of 230 VAC between LD66B and X64 on the inverter P.C. board?
Check the power supply and correct them.
Replace the outdoor display P.C. board.
Replace the inverter P.C. board.
Is there voltage of 230 VAC between LD66A and LD70 on the inverter P.C. board?
Replace the reactor.
Is there voltage of 325 VDC between DB61 and DB61 on the inverter P.C. board?
Replace the inverter P.C. board.
Is there voltage of 5 VDC between CN936 and CN936 on the outdoor display P.C. board?
Check the connected wire between the inverter P.C. board and outdoor display P.C. board and correct it.Replace the inverter P.C. board.
MXZ-2DM40VA
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MXZ-3DM50VA
Check the main power supply circuit for proper connections.
Is there voltage of 230 VAC in the power supply terminal block?
Is the output voltage from the noise filter P.C. board 230 VAC?
Is the input voltage to the outdoor electronic control P.C. board 325 VDC?
Check the power supply and correct them.
Replace the outdoor control P.C. board.
Replace the noise filter P.C. board.
Is the input voltage to the power P.C. board 230 VAC? Replace the reactor.
Turn ON the breaker.
No
Yes
Yes
No
Yes
No
Yes
No Replace the outdoor power P.C. board.
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LED indication for communication status
Communication status is indicated by the LED.
Unit status NoBlinking: normal communicationLighted: abnormal communication or not connected
seYNot lighted: The outdoor P.C. board is abnormal.NOTE: "Lighted" and "Not lighted" in the table below
does not indicate abnormal. *1 Turn OFF the breaker before replacing the indoor electronic control P.C. board. Refer to indoor unit service manual.
oNoN
Yes
oN A
A
seY
seY
No
Yes
No (Lighted or not lighted)
*1 Turn OFF the breaker before replacing the indoor electronic control P.C. board. Refer to indoor unit service manual.*3 Turn OFF the breaker before replacing the inverter P.C. board. Be careful of residual voltage of smoothing capacitor.*4 Remove the short-circuit between outdoor terminal block S2 and S3. Connect the indoor/outdoor connecting wire.
Turn ON the breaker.
Is there rated voltagebetween outdoorterminal block S1 and S2?
Check the power supply and correct the problem.
Press the EMERGENCY OPERATION switch once.
Does the OPERATIONINDICATOR lamp lightup? <Confirmation ofthe power to the indoorunit>
Is there ratedvoltage betweenoutdoor terminalblock S1 and S2?
Check the indoor/outdoor connecting wire and correct the problem.
Replace the indoor electronic control P.C. board. *1
Is serial signal errorindicated 6 minuteslater?
Is there any miswiring,poor contact, or wiredisconnection of theindoor/outdoorconnecting wire?
Check the indoor/outdoor connecting wire and correct the problem.
Turn OFF the breaker.
Turn ON the breaker.
Does the LED on theoutdoor display P.C.board or the outdoor control P.C. board repeat quickBLINKING and OFF? *2
Replace the indoor electronic control P.C. board. *1 *4
*2 The LED indicates the status of serial communication. Check the communication status.
Replace the inverter P.C.board or the outdoor control P.C. board. *3 *4
If the trouble sometimes occurs, possible causes are as follows:
outdoor connecting wireCheck for intermediate connection of the indoor/outdoor connecting wire, loose connection to the terminal block, and cut wire inside the cable. If any of them is found, correct the problem(s).
on the indoor unit If the trouble occurs or does not occur depending on whether the light is on or off, distance the lighting from the indoor unit or apply the glass filter on the receiving part of the indoor unit.
connecting wirePass the indoor/outdoor connecting wire through a different route if the existing wiring is arranged as below:
runs near the power supply cable of other equipment.
is detoured and run long.
Remove the indoor/outdoor connecting wire from the outdoor terminal block connected with the indoor unit on which miswiring or the serial signal error is indicated. Short-circuit between S2 and S3 of the outdoor terminal block.
Outdoor control P.C. board
Blinking
LED3 LED2 LED1
LED 3 LED 1LED 2Pattern
1
2
Unit BstatusLighted Unit A
status
-Not lighted Unit Cstatus
MXZ-3DM50VA
MXZ-2DM40VAOutdoor display P.C. board
LED 1 LED 2Unit A Unit Bstatus status
LED1 LED2
How to check miswiring and serial signal error (when outdoor unit does not work)
• When the indoor unit does not operate, it cannot be operated either with the remote controller or with the EMERGENCY OPERATION switch.
• When the outdoor unit does not operate, the OPERATION INDICATOR lamp on the indoor unit flashes ON and OFF every 0.5-second.
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How to check inverter/compressor
No
No
Yes
Yes
No
Yes
No
Yes
Disconnect the connector (CNMC) between the inverter P.C. board/the outdoor control P.C. board and compressor, or disconnet the terminal of the compressor.3 minutes after turning ON the breaker, start EMERGENCY OPERATION.
Is output balanced? Replace the inverter P.C. board orthe outdoor power P.C. board.
(MXZ-3DM50VA)Is the input voltage to the outdoor control P.C. board 370 VDC or more?
Replace the outdoor power P.C. board.
Replace the compressor.
Measure the voltage between each lead wire leading to the compressor.U (BLK) - V (WHT)V (WHT) - W (RED)W (RED) - U (BLK)Is there voltage of 50 VAC - 250 VAC? * 1, * 2
Turn OFF the breaker, and measure the compressor winding resistance between the compressor terminals.Is there resistance between each terminal normal? (Refer to 11-5.)
Reconnect the lead wire of compressor.3 minutes after turning ON the breaker, start EMERGENCY OPERATION.
Clarify the causes by counting time until the inverter stops.0 to 10 seconds: compressor layer short10 to 60 seconds: compressor lock60 seconds to 5minutes: refrigerant circuit defective 5 minutes or more: normal
* 1 After the outdoor fan starts running, wait for 1 minute or more before measuring the voltage.
The output voltage values have the tolerance of ± 20%.* 2 The output differs depending on the capacity or the
number of indoor units to be operated.
• In heating, the room does not get warm.• In cooling, the room does not get cool.
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Check of outdoor thermistors
• The thermistor is abnormal.
Is the resistance of the thermistor normal? (Refer to 11-5.)
Disconnect the connector in the following table.
Does the unit operate 10 minutes or more withoutshowing thermistor abnormality?
Replace the thermistor except RT64.In case that RT64 is abnormal,replace the inverter P.C. board or theoutdoor power P.C. board since RT64 is combined with this board.
Normal
Replace the inverter P.C. board, outdoor control P.C. board or the outdoor power P.C. board.
Yes
Yes
No
No
Reconnect the connector and disconnect the lead wire leading to the compressor.3 minutes after turning ON the breaker, start EMERGENCY OPERATION.
ThermistorDefrostDischarge temperatureFin temperatureAmbient temperatureOutdoor heat exchanger temperature
SymbolRT61RT62RT64RT65RT68
Connector, Pin No.CN641 pin1 and pin2CN641 pin3 and pin4CN642 pin1 and pin2CN643 pin1 and pin2CN644 pin1 and pin3
Inverter P.C. board
Outdoor control P.C. board
Outdoor power P.C. boardOutdoor control P.C. board
Board
ThermistorDefrostDischarge temperatureFin temperatureAmbient temperatureOutdoor heat exchanger temperature
SymbolRT61RT62RT64RT65RT68
Connector, Pin No.CN661 pin1 and pin2CN661 pin3 and pin4CN9 pin1 and pin2CN665 pin1 and pin2CN661 pin7 and pin8
BoardMXZ-3DM50VA
MXZ-2DM40VA
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Check of LEV
No
Yes
Yes
No
Turn ON the breaker to the outdoor unit after checking LEV coil is mounted to the LEV body securely.
Is "click - click" sound heard?Or, do you feel vibration of LEV coil with your hand?
Disconnect the connectors.MXZ-2DM40VACN724: LEV A, CN725: LEV BMXZ-3DM50VACN791: LEV A, CN792: LEV B, CN793: LEV C, CN795: LEV E
Normal
Is the resistance of the LEV coil normal? (Refer to 11-5.)
Replace the inverter P.C. board or the outdoor control P.C. board.
Replace LEV coil.
• In cooling, the heat exchanger of non-operating indoor unit has frosted.• In heating, non-operating indoor unit gets warm.
MXZ-2DM40VA MXZ-3DM50VACN724CN725 Inverter P.C. board ―
CN791CN792CN793CN795
― Outdoor control P.C. board
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Check of outdoor fan motor
• Fan motor does not operate or stops operating shortly after starting the operation.
Disconnect CN932 and measure the resistance of the outdoor fan motor.
Turn ON the breaker.Rotate the outdoor fan motor manually and measure the voltage of CN931.Between (+) and (-)Between (+) and (-)Between (+) and (-)
Is the resistance of outdoor fan motor normal? (Refer to 11-5.)
Does the outdoor fan motor rotate smoothly?
Does the voltage between each terminal become 5 VDC and 0 VDC repeatedly?
Replace the outdoor fan motor.Replace the inverter P.C. board or the outdoor control P.C. board.
No
Yes
YesNo
Yes
No
MXZ-2DM40VA
CN931CN932 Inverter P.C. board
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MXZ-3DM50VA
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Disconnect CN931 and measure the resistance of the outdoor fan motor.
Is the resistance of outdoor fan motor normal? (Refer to right table)
Turn on the power supply to start operation and measure the voltage of connector CN931.
Turn OFF the power supply and connect the connector CN931.Turn ON the power supply and measure the voltage of connector CN931 while rotating the motor by the hand.
Does the outdoor fan motor rotate smoothly?
Replace the outdoor fan motor. ResistanceMeasuring points
* To measure the resistance, connect the negative (-) end of the tester to pin4.
* To measure the voltage, connect the negative (-) end of the tester to pin4.* Voltage between pin4 and 6 should be measured within 1 minute after the operation starts.
pin1 - pin4pin5 - pin4pin6 - pin4pin7 - pin4
Voltage
15 VDC325 VDC
1 - 5 VDC
CN931pin1 - pin4pin5 - pin4pin6 - pin4
Is the voltage of connector CN931normal? (Refer to right table.) Replace the outdoor control P.C. board.
Does the voltage between pin7 and pin4 of connector CN931 repeat 0 VDC and 5 VDC? Replace the outdoor fan motor.
Does the fan motor operate for about 5 seconds? Replace the outdoor fan motor.
Replace the outdoor fan motor.
Replace the outdoor control P.C. board.
Start operation.
CN931 Outdoor control P.C. board
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Check of R.V. coil
No
Yes
No
Yes
Yes
No
1. Disconnect the lead wire leading to the compressor.2. 3 minutes after turning ON the breaker, start EMERGENCY OPERATION in HEAT mode.
Is there voltage of 230 VAC between pin1 and pin2 at connector CN721?
Turn OFF the breaker. Disconnect the connector CN721.
Replace the inverter P.C. board.
Replace the 4-way valve.
Replace the R.V. coil.Is there normal resistanceto R.V. coil? (Refer to 11-5.)
1. Disconnect the lead wire leading to the compressor.2. 3 minutes after turning ON the breaker, start EMERGENCY OPERATION in COOL mode.
Is there voltage of 230 VAC between pin1 and pin2 at connector CN721? Replace the inverter P.C. board.
Replace the 4-way valve.
The cooling operation or the heating operation does not operate.
MXZ-2DM40VA CN721 Inverter P.C. board
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No
Yes
No
Yes
No
Yes
No
Yes
1. Disconnect the lead wire leading to the compressor.2. 3 minutes after turning ON the breaker, start EMERGENCY OPERATION in HEAT mode.
Is there voltage of 230 VAC between pin1 and pin2 at connector CN712?
Turn OFF the breaker.Disconnect the connector CN712.
Replace the 4-way valve.
Replace the outdoor control P.C. board.
Replace the R.V. coil.
Is there voltage 230 VAC between the pin1 and pin3 atconnector CN711?
Replace the noise filter P.C. board.
Is there normal resistance to R.V. coil? (Refer to 11-5.)
1. Disconnect the lead wire leading to the compressor.2. 3 minutes after turning ON the breaker, start EMERGENCY OPERATION in COOL mode.
Is there voltage of 230 VAC between pin1 and pin2 at connector CN712? Replace the 4-way valve.
Replace the outdoor control P.C. board.
CN711CN712 Outdoor control P.C. board
MXZ-3DM50VA
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Check of HPS
Infinity
Yes
No
1. Disconnect the connector CN681.2. Check the resistance of HPS 1 minute after the outdoor unit breaker was turned OFF.
Check the resistance between each terminal.
Reconnect CN681.Turn ON the breaker to the indoor and the outdoor units.3 minutes later, start EMERGENCY OPERATION.
Is HPS protection displayed immediately after compressor starts?
Replace HPS.
Replace the outdoor control P.C. board.
Normal
• When the operation frequency does not go up from lowest frequency.
MXZ-3DM50VA CN681 Outdoor control P.C. board
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The other cases
Check of outdoor refrigerant circuit
Indoor unit does not operate. (different operating models in multi system)
• When you try to run 2 indoor units simultaneously, one for cooling and the other for heating, the unit which transmits signal to the outdoor unit first decides the operation mode.
• When the above situation occurs, set all the indoor units to the same mode, turn OFF the indoor units, then turn them back ON.
• Though the top of the indoor unit sometimes gets warm, this does not mean malfunction. The reason is that the refrigerant gas continuously flows into the indoor unit even while it is not operating.
Check of bus-bar voltage
•Check the voltage of power supply. •Confi rm outdoor unit failure mode recall function. (Refer to 11-2.2.)
Blink 5 times
Confi rm LED1 indication lamp on the outdoor control P.C. board.
Replace the power P.C. board.
Blink 9 times
Replace the outdoor control P.C. board.
Turn OFF the breaker before removing P.C. board.
Confi rm LED1 indication lamp on the outdoor control P.C. board.
Turn ON the breaker. Start operation.
Blink 6 times
Replace the outdoor control P.C. board .
Lighting
Replace the outdoor control P.C. board.
Blink 9 times
Replace the power P.C. board.
Confi rm LED1 indication lamp on the outdoor control P.C. board.
Turn ON the breaker. Start operation.
NormalLighting Lighting
MXZ-3DM50VA
Has the operation stopped during pump down?
Was the operation started with the stop valve closed, and was it opened during operation?No
Yes
The operation has stopped to pre-vent the diesel explosion caused by air trapped in the refrigerant circuit. Close the stop valve, and disconnect the power plug or turn the breaker OFF.
The unit occasionally stops when the stop valve is opened or closed during operation. Open the stop valve and start the cooling operation again.
Yes
No
The refrigerant gas amount may be 60% or less than the normal amount. Identify where the gas is leaking from, and fi x the leak.
CAUTION: Do not start the opera-tion again to prevent hazards.
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11-7. TEST POINT DIAGRAM AND VOLTAGE
MXZ-2DM40VA1. Inverter P.C. board
Back side of unit
Connect tooutdoor dis-play P.C. board(CN935)
Fin temperaturethermistor/RT64 (CN642)
Ambient temperature thermistor /RT65 (CN643)
Discharge temperature thermistor/RT62 (CN641)
Defrost thermistor/RT61 (CN641)
230 VAC (LD66A, LD70)
Front side of unit
250 - 325 VDC(DB61(+), (-))
Output to drive compressor(LDU, LDV, LDW)
FUSE (F801)T3.15AL250V
FUSE (F901)T3.15AL250V
Signal of outdoor fan motor (CN931)
Outdoor heat exchanger temperature thermistor /RT68 (CN644)
Smoothing capacitor(C61, C62, C63)
R.V. coil (CN721)
FUSE (F701)T3.15AL250V
230 VAC (X64 , LD66B)
230 VAC (LD61, LD62)
230 VAC (CN601 , )Serial signal A(CN601 , )Serial signal B(CN601 , CN602 ,)
Output to driveoutdoor fan motor (CN932)
LEV A coil (CN724)LEV B coil
(CN725)
Temperature (°C)
Discharge temperature thermistor (RT62)
0
100
200
300
400
500
600
700
800
0 10 20 30 40 50 60 70 80 90 100 110 120-20 -10 0 10 20 30 400
10
20
30
40
50
60
70
80
90
100
Temperature (°C)
Defrost thermistor(RT61)Ambient temperature thermistor(RT65)Outdoor heat exchanger temperature thermistor(RT68)
0 10 20 30 40 50 60 70 800
20
40
60
80
100
120
140
160
180
200Fin temperature thermistor(RT64)
Res
ista
nce(
k )
Res
ista
nce(
k )
Temperature (°C)
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2. Outdoor control P.C. board
LED 1LED 2
CN801Bus-bar voltage325 - 370 VDC Input
(
LEV
Roo
m
A(
12 V
DC
puls
e w
ave
(
LEV
Roo
m
B(
12 V
DC
puls
e w
ave
(
LEV
Roo
m
C(
12 V
DC
puls
e w
ave
(Hi
gh p
ress
ure
switc
h
Def
rost
ther
mis
tor (
RT6
1)D
isch
arge
tem
pera
ture
ther
mis
tor (
RT6
2)
Out
door
hea
t exc
hang
er
tem
pera
ture
ther
mis
tor (
RT6
8)
( ((+)
(–)
(+)
(–)
(
CN
661
Sig
nal t
rans
mis
sion
(To
pow
er P
.C. b
oard
)5
VD
C p
ulse
wav
e
LEV
E((+)
(–) ((+)
(–) ((+)
(–) ( CN
791
CN
792
CN
793
CN
681
( ( (
F801 FUSET3.15AL250V
(
Am
bien
t tem
pera
ture
ther
mis
tor (
RT6
5)C
N66
5
Serial signal Room C12 - 24 VDC
Serial signal Room B12 - 24 VDC
Serial signal Room A12 - 24 VDC
CN621
CN611
CN601
Input
SW2
CN
795
12 V
DC
puls
e w
ave
Temperature (°C)
Discharge temperature thermistor (RT62)
0
100
200
300
400
500
600
700
800
0 10 20 30 40 50 60 70 80 90 100 110 120-20 -10 0 10 20 30 40
100
90
80
70
60
50
40
30
20
10
0
Defrost thermistor (RT61)Ambient temperature thermistor (RT65)Outdoor heat exchanger temperature thermistor (RT68)
Temperature (°C)
Res
ista
nce
(kΩ
)
MXZ-3DM50VA
CN
701
15V
15V
(+)
(–)
(S
igna
l rec
eptio
n(F
rom
pow
er P
.C. b
oard
)5
VD
C p
ulse
wav
e
CN
702
F930 FUSET3.15AL250V
CN931To Fan motor
CN
931
Bus
-bar
vol
tage
325
- 370
VD
CIn
put
15 V
DC
Rot
ate
inst
ruct
ion
Rot
ate
sign
al
230 VAC
CN711230 VAC
F711 FUSE T3.15AL250V
CN712R.V .coil
SW871
LED 3
(–)
OBH739A
48
MXZ-3DM50VA3. Outdoor power P.C. board
Connect to the compressorVoltage among phases: 5V to 180V
Connect to the earth
CN5Primary current detection(Connect to the noise filter)
CN2Connect to the controller board(+)1-5(–): Signal transmission (To electronic control P.C. board) 5 VDC pulse wave(+)2-5(–): Zero cross signal 3-4 : Not used(+)6-5(–): 15V(+)7-5(–): 15V
325 - 370 VDCOutput
(Red)
(White)
(+)
(–)
1
3
0 10 20 30 40 50 60 70 80
200
180
160
140
120
100
80
60
40
20
0
Res
ista
nce
(kΩ
)
Temperature (°C)
Fin temperature thermistor (RT64)
Signal reception (From electronic control P.C. board) 5 VDC pulse wave
(
CN9Fin temperature thermistor RT64
MXZ-2DM40VA4. Outdoor display P.C. board
SW1
GND5V
LED2LED1
To inverter P.C. board (CN936))
SW2
OBH739A
49
MXZ-3DM50VA5. Noise filter P.C. board
230 VACOutput
F64 FUSET2AL250V
{
CN901To powerP.C. board{
CN904To power P.C. board
CN903To power P.C. board
CN62To outdoor control P.C. board
F65FUSET6.3AL250V
CN61230 VAC Output
{
OBH739A
12-1. MXZ-2DM40VANOTE: Turn OFF the power supply before disassembly.
OPERATING PROCEDURE PHOTOS1. Removing the cabinet and the panels
(1) Remove the screw fixing the service panel.(2) Pull down the service panel and remove it.(3) Disconnect the power supply and indoor/outdoor con-
necting wire.(4) Remove the screws fixing the top panel.(5) Remove the top panel.(6) Remove the screws fixing the cabinet.(7) Remove the cabinet.(8) Remove the screws fixing the back panel.(9) Remove the back panel.
50
DISASSEMBLY INSTRUCTIONS12
(1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with this connector has the locking mechanism.
Slide the sleeve. Pull the terminal while pushing the locking lever.
Hold the sleeve, and pull out the terminal slowly.
The terminal which has the locking mechanism can be detached as shown below.There are 2 types ( Refer to (1) and (2)) of the terminal with locking mechanism.The terminal without locking mechanism can be detached by pulling it out.Check the shape of the terminal before detaching.
<"Terminal with locking mechanism" Detaching points>
Connector
Sleeve
Locking lever
Photo 1
Screws of the Service panel
Screws of the top panel
Screws of the cabinet
Screws of the terminal block support and the back panel
Photo 2
HooksPhoto 3
Screws of the back panel
Direction to remove
OBH739A
OPERATING PROCEDURE PHOTOS2. Removing the inverter assembly and the inverter
P.C. board(1) Remove the service panel, the top panel and the cabi-
net (Refer to 1).(2) Disconnect the power supply and indoor/outdoor con-
necting wire and remove the back panel (Refer to 1).(3) Disconnect all connectors and lead wires on the
inverter P.C. board.(4) Remove the compressor connector (CNMC).(5) Remove the screws fixing the heat sink support and
the separator.(6) Remove the screws of the terminal block support and
the back panel. (Photo 2)(7) Remove the inverter assembly.(8) Remove the screw of the earth wire and screws of the
terminal block support.(9) Remove the hooks of the heat sink support and
remove the heat sink support from the P.C. board support.
(10) Remove the screw fixing the inverter P.C. board and remove the inverter P.C. board from the P.C. board support.
3. Removing the R.V. coil (1) Remove the service panel, the top panel and the cabi-
net (Refer to 1).(2) Disconnect the power supply and indoor/outdoor con-
necting wire and remove the back panel (Refer to 1).(3) Remove the inverter assembly (Refer to 2).(4) Remove the R.V. coil.
4. Removing the discharge temperature thermistor, defrost thermistor and outdoor heat exchanger temperature thermistor (1) Remove the service panel, the top panel and the cabi-
net (Refer to 1).(2) Disconnect the power supply and indoor/outdoor con-
necting wire and remove the back panel (Refer to 1).(3) Remove the inverter assembly (Refer to 2).(4) Pull out the discharge temperature thermistor from its holder.(5) Pull out the defrost thermistor from its holder (Photo 7).(6) Pull out the outdoor heat exchanger temperature ther-
mistor from its holder (Photo 7).
51
Photo 6
Photo 4
Photo 5
Screws of the heat sink support and the separator
Discharge temperature thermistor (RT62)
Reactor (ACL)
Screws of the terminalblock support
Reactor (ACL2)
Compressorconnector
Inverterassembly
Hooks of the heat sink support
P.C. board support
Screw of the earth wireScrew of the inverter P.C. board
R.V. coil
OBH739A
OPERATING PROCEDURE PHOTOS5. Removing the outdoor fan motor
(1) Remove the service panel, the top panel and the cabi-net (Refer to 1).
(2) Disconnect the power supply and indoor/outdoor con-necting wire.
(3) Disconnect the connectors for outdoor fan motor.(4) Remove the propeller fan nut. (5) Remove the propeller fan.(6) Remove the screws fixing the fan motor.(7) Remove the fan motor.
6. Removing the compressor and the 4-way valve(1) Remove the service panel, the top panel and the cabi-
net (Refer to 1).(2) Disconnect the power supply and indoor/outdoor con-
necting wire and remove the back panel (Refer to 1).(3) Remove the inverter assembly (Refer to 2).(4) Recover gas from the refrigerant circuit.NOTE: Recover gas from the pipes until the pressure
gauge shows 0 kg/cm2 (0 MPa).(5) Detach the brazed part of the suction and the dis-
charge pipe connected with compressor.(6) Remove the nuts of compressor legs.(7) Remove the compressor.(8) Detach the brazed part of pipes connected with 4-way
valve.
52
Defrostthermistor (RT61)
Ambient temperaturethermistor (RT65)
Photo 9
Photo 8Screws of the fan motor
Outdoor heatexchangertemperaturethermistor (RT68)
Propeller fan
Brazed parts of 4-way valve
Propeller fan nut
Photo 7
Photo 10
Suction pipe brazed part
Discharge pipe brazed part
Compressor nuts
OBH739A
12-2. MXZ-3DM50VANOTE: Turn OFF the power supply before disassembly.
OPERATING PROCEDURE PHOTOS1. Removing the cabinet and the panels
(1) Remove the screws of the service panel, and remove the service panel.
(2) Remove the screws of the top panel, and remove the top panel.
(3) Disconnect the power supply and indoor/outdoor con-necting wire.
(3) Remove the screws of the cabinet, and remove the cabinet.
(4) Remove the screws of the back panel, and remove the back panel (Photo 3).
53
Photo 2
Photo 1
Screws of the cabinet
Screws of the top panel
Screw of the cabinet
Screws of the cabinet
Screws of the service panel
Screw of the top panel
Screws of the cabinet
Screws of the cabinet
Screws of thesub panel
Photo 3 Screw of the rear guard
Screws of the back panel
Screws of the back panel
Screws of the back panel
Screws of the back panel
OBH739A
OPERATING PROCEDURE PHOTOS2. Removing the outdoor control P.C. board, the
outdoor power P.C. board and the noise filter P.C. board(1) Remove the service panel (Refer to 1).(2) Remove the top panel, the cabinet, and the back
panel (Refer to 1).(3) Disconnect all connectors and lead wires on the out-
door control P.C. board.(4) Remove the outdoor control P.C. board.(5) Remove the screws fixing the outdoor power P.C.
board.(6) Disconnect all connectors and lead wires on the out-
door power P.C. board.(7) Pull up the power P.C. board and remove it upward.(8) Disconnect all connectors and lead wires on the noise
filter P.C. board.(9) Remove the noise filter P.C. board.
3. Removing the reactor(1) Remove the service panel (Refer to 1).(2) Remove the top panel, cabinet, back panel, and the
electrical parts (Refer to 1 and 2).(3) Disconnect the reactor lead wire from the terminal of
the reactor.(4) Remove the screws of the reactor, and remove the
reactor.
4. Removing the fan motor(1) Remove the service panel, the top panel, and the
cabinet (Refer to 1).(2) Disconnect the connector CN931 on the outdoor con-
trol P.C. board.(3) Remove the propeller fan.(4) Remove the fan motor.
54
Photo 7Screws of the outdoor fan motor
Propeller fan Propeller fan nut Separator
Sound proof felt
Photo 4
Screws of the electrical parts
Photo 5
Screws of the outdoor power P.C. board
Photo 6
Screws of the reactor
OBH739A
OPERATING PROCEDURE PHOTOS5. Removing the compressor and the 4-way valve
(1) Remove the service panel (Refer to 1).(2) Remove the top panel, the cabinet, and the back
panel (Refer to 1).(3) Recover gas from the refrigerant circuit.NOTE: Recover gas from the pipes until the pressure
gauge shows 0 kg/cm2 (0 MPa).(4) Disconnect the compressor lead wire from terminal of
the compressor (U, V, W).(5) Disconnect the outdoor control P.C. board connectors: CN661, CN665, CN681 CN711, CN712, CN791,
CN792, CN793, CN795, CN931(6) Remove the screws of the electrical parts, and remove
the electrical parts (Photo 4).(7) Remove the propeller fan.(8) Remove the screws of the separator, and remove the
separator (Photo 7).(9) Remove the sound proof felt (Photo 7).(10) Detach the brazed parts of the compressor suction
and discharge pipes.(11) Remove the compressor nuts and remove the com-
pressor.(12) Detach the brazed parts of 4-way valve and pipe.
6. Removing the expansion valve(1) Remove the service panel (Refer to 1).(2) Remove the top panel, the cabinet, and the back
panel (Refer to 1). (Gas recovery is not required if the unit is pumped down.)(3) Remove the electrical parts for removing LEV E (Photo
4, 8).(4) Remove the LEV coils.(5) Detach the brazed parts of expansion valves and
pipes.
55
Photo 8R.V. coil 4 way valve LEV coil E
Expansion valve E
Suction pipebrazed part
Discharge temperature thermistor (RT62)
Discharge pipe brazed part
Compressor nuts
4-way valve
R.V. coil
Expansion valves
Photo 9
Photo 10
LEV coils
Brazed parts
Defrost thermistor (RT61)
Ambient temperaturethermistor (RT65)
Outdoor heatexchangertemperaturethermistor (RT68)
OBH739A
MXZ-2DM40VA COOLINGCurrent Power
Unit A Unit B (A) factor(%)
( 0.90 - 2.80 ) ( 0.147 - 0.686 )
( 0.90 - 3.15 ) ( 0.147 - 0.830 )
( 1.10 - 4.30 ) ( 0.275 - 1.424 )
( 1.10 - 4.40 ) ( 0.275 - 1.460 )
Indoor units Cooling capacity (kW) Outdoor unitcombination Total power consumption(kW)
90
35 3.15 -3.15 0.830
4.01 90
25 2.50 -2.50 0.617
2.98
90
25+35 1.67 2.334.00 1.014
4.90 90
25+25 2.00 2.004.00 1.014
4.90
1/4OBH739_COMBINATION
MXZ-2DM40VA HEATINGCurrent Power
Unit A Unit B (A) factor(%)
( 0.90 - 4.00 ) ( 0.136 - 1.123 )
( 0.90 - 4.30 ) ( 0.131 - 1.235 )
( 1.00 - 4.70 ) ( 0.176 - 1.250 )
( 1.00 - 4.80 ) ( 0.181 - 1.282 )
Indoor units Heating capacity (kW) Outdoor unitcombination Total power consumption(kW)
90
35 3.60 -3.60 0.939
4.54 90
25 3.15 -3.15 0.770
3.72
1.1155.39 90
25+25 2.15 2.154.30 1.120
5.41 90
25+35 1.79 2.514.30
2/4OBH739_COMBINATION
MXZ-3DM50VA COOLINGCurrent Power
Unit A Unit B Unit C (A) factor(%)
( 1.90 - 3.30 ) ( 0.571 - 0.847 )
( 2.00 - 4.30 ) ( 0.585 - 1.204 )
( 3.60 - 5.60 ) ( 1.110 - 1.693 )
( 1.90 - 5.70 ) ( 0.537 - 1.271 )
( 1.90 - 6.50 ) ( 0.537 - 2.620 )
( 1.90 - 6.50 ) ( 0.547 - 2.610 )
( 1.90 - 6.50 ) ( 0.537 - 2.620 )
( 1.90 - 6.50 ) ( 0.557 - 2.595 )
( 2.70 - 6.50 ) ( 0.666 - 2.296 )
( 2.70 - 6.50 ) ( 0.666 - 2.296 )
Indoor units Cooling capacity (kW) Outdoor unitcombination Total power consumption(kW)
-4.60 1.149
5.05
99
50 5.00 -5.00 1.604
7.04 99
25 2.50 -2.50 0.671
2.95-
-
-
2.30
99
35 3.15 -3.15 0.838
3.68 99
25+50 1.67 -5.00 1.264
5.55
99
25+35 2.08 -5.00 1.264
5.55 99
25+25 2.30
99
35+35 2.50 -5.00 1.264
5.55 99
35+50 2.06 -5.00 1.261
5.54
2.92
3.33
2.50
2.94
1.47
4.73 9925+25+25 1.67 1.67 1.675.00 1.076
9925+25+35 1.47 2.065.00 1.076
4.73
3/4OBH739_COMBINATION
MXZ-3DM50VA HEATINGCurrent Power
Unit A Unit B Unit C (A) factor(%)
( 3.15 - 4.50 ) ( 0.956 - 1.238 )
( 3.60 - 4.50 ) ( 1.108 - 1.268 )
( 3.70 - 7.90 ) ( 1.005 - 2.216 )
( 1.70 - 7.50 ) ( 0.484 - 1.852 )
( 1.70 - 7.50 ) ( 0.484 - 1.852 )
( 1.70 - 7.50 ) ( 0.484 - 1.828 )
( 1.70 - 7.50 ) ( 0.484 - 1.852 )
( 1.70 - 7.50 ) ( 0.484 - 1.788 )
( 2.40 - 7.50 ) ( 0.590 - 1.660 )
( 2.40 - 7.50 ) ( 0.590 - 1.660 )
Indoor units Heating capacity (kW) Outdoor unitcombination Total power consumption(kW)
4.20 99
35 3.60 - -3.60 1.108
4.87 99
25 3.15 - -3.15 0.956
6.42 99
25+25 2.90 2.90 -5.80 1.309
5.75 99
50 5.40 - -5.40 1.462
5.75 99
25+50 1.93 3.87 -5.80 1.259
5.53 99
25+35 2.42 3.38 -5.80 1.309
5.75 99
35+50 2.39 3.41 -5.80 1.182
5.19 99
35+35 2.90 2.90 -5.80 1.309
5.49 99
25+25+35 1.76 1.76 2.476.00 1.250
5.49 99
25+25+25 2.00 2.00 2.006.00 1.250
4/4OBH739_COMBINATION
Copyright 2015 MITSUBISHI ELECTRIC CORPORATIONDistributed in Mar. 2016. No.OBH739 REVISED EDITION-ADistributed in Dec. 2015. No.OBH739Made in Japan
New publication, effective Mar. 2016Specifications are subject to change without notice.
HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN